inputcontext.java

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          InputMethodDescriptor d = (InputMethodDescriptor) descriptors.get(i);
          Locale[] list;
          try
            {
              list = d.getAvailableLocales();
            }
          catch (AWTException ignored)
            {
              continue;
            }
          for (int j = list.length; --j >= 0; )
            if (locale.equals(list[j]))
              {
                try
                  {
                    next = d.createInputMethod();
                    recent.put(locale, next);
                  }
                catch (Exception ignored)
                  {
                    continue;
                  }
              }
        }
    if (next == null)
      return false;
    // XXX I'm not sure if this does all the necessary steps in the switch.
    if (im != null)
      {
        try
          {
            next.setCompositionEnabled(im.isCompositionEnabled());
          }
        catch (UnsupportedOperationException ignored)
          {
          }
        im.endComposition();
        im.deactivate(false);
        im.hideWindows();
      }
    im = next;
    im.setLocale(locale);
    im.setCharacterSubsets(subsets);
    return true;
  }

  /**
   * Returns the current locale of the current input method or keyboard
   * layout. Returns null if the input context does not have a current input
   * method or keyboard layout or if the current input method's
   * {@link InputMethod#getLocale()} method returns null. Not all host
   * operating systems provide API to determine the locale of the currently
   * selected native input method or keyboard layout. For host operating
   * systems that don't provide such API, getLocale assumes that the current
   * locale of all native input methods or keyboard layouts provided by the
   * host operating system is the system's default locale.
   *
   * @return the locale of the current input method, or null
   * @since 1.3
   */
  public Locale getLocale()
  {
    return im == null ? null : im.getLocale();
  }

  /**
   * Sets the subsets of Unicode characters allowed to be input by the current
   * input method, as well as subsequent input methods. The value of null
   * implies all characters are legal. Applications should not rely on this
   * behavior, since native host input methods may not allow restrictions.
   * If no current input method is available, this has no immediate effect.
   *
   * @param subsets the set of Unicode subsets to accept, or null
   */
  public void setCharacterSubsets(Character.Subset[] subsets)
  {
    this.subsets = subsets;
    if (im != null)
      im.setCharacterSubsets(subsets);
  }

  /**
   * Changes the enabled status of the current input method. An input method
   * that is enabled for composition interprets incoming events for both
   * composition and control purposes, while a disabled input method only
   * interprets control commands (including commands to enable itself).
   *
   * @param enable whether to enable the input method
   * @throws UnsupportedOperationException if there is no current input method,
   *         or the input method does not support enabling
   * @see #isCompositionEnabled()
   * @since 1.3
   */
  public void setCompositionEnabled(boolean enable)
  {
    if (im == null)
      throw new UnsupportedOperationException();
    im.setCompositionEnabled(enable);
  }

  /**
   * Find out if the current input method is enabled.
   *
   * @return true if the current input method is enabled
   * @throws UnsupportedOperationException if there is no current input method,
   *         or the input method does not support enabling
   * @see #setCompositionEnabled(boolean)
   * @since 1.3
   */
  public boolean isCompositionEnabled()
  {
    if (im == null)
      throw new UnsupportedOperationException();
    return im.isCompositionEnabled();
  }

  /**
   * Starts a reconversion operation in the current input method. The input
   * method gets theh text to reconvert from the client component, using
   * {@link InputMethodRequests#getSelectedText(Attribute[])}. Then the
   * composed and committed text produced by the operation is sent back to
   * the client using a sequence of InputMethodRequests.
   *
   * @throws UnsupportedOperationException if there is no current input method,
   *         or the input method does not support reconversion
   * @since 1.3
   */
  public void reconvert()
  {
    if (im == null)
      throw new UnsupportedOperationException();
    im.reconvert();
  }

  /**
   * Dispatches an event to the current input method. This is called
   * automatically by AWT. If no input method is available, then the event
   * will never be consumed.
   *
   * @param event the event to dispatch
   * @throws NullPointerException if event is null
   */
  public void dispatchEvent(AWTEvent event)
  {
    if (im != null)
      im.dispatchEvent(event);
  }

  /**
   * Notifies the input context that a client component has been removed from
   * its containment hierarchy, or that input method support has been disabled
   * for the component. This method is usually called from the client
   * component's {@link Component#removeNotify()} method. Potentially pending
   * input from input methods for this component is discarded. If no input
   * methods are available, then this method has no effect.
   *
   * @param client the client component
   * @throws NullPointerException if client is null
   */
  public void removeNotify(Component client)
  {
    // XXX What to do with client information?
    if (im != null)
      {
        im.deactivate(false);
        im.removeNotify();
      }
  }

  /**
   * Ends any input composition that may currently be going on in this
   * context. Depending on the platform and possibly user preferences, this
   * may commit or delete uncommitted text. Any changes to the text are
   * communicated to the active component using an input method event. If no
   * input methods are available, then this method has no effect. This may
   * be called for a variety of reasons, such as when the user moves the
   * insertion point in the client text outside the range of the composed text,
   * or when text is saved to file.
   */
  public void endComposition()
  {
    if (im != null)
      im.endComposition();
  }

  /**
   * Disposes of the input context and release the resources used by it.
   * Called automatically by AWT for the default input context of each
   * Window. If no input methods are available, then this method has no
   * effect.
   */
  public void dispose()
  {
    if (im != null)
      {
        im.deactivate(false);
        im.dispose();
      }
  }

  /**
   * Returns a control object from the current input method, or null. A
   * control object provides implementation-dependent methods that control
   * the behavior of the input method or obtain information from the input
   * method. Clients have to compare the result against known input method
   * control object types. If no input methods are available or the current
   * input method does not provide an input method control object, then null
   * is returned. 
   *
   * @return the control object, or null
   */
  public Object getInputMethodControlObject()
  {
    return im == null ? null : im.getControlObject();
  }
} // class InputContext